1. Field of the Invention
The present invention relates to a steering system of a vehicle, particularly, it relates to a steering system of a vehicle in which a steering handle and steering mechanisms of wheels are separated mechanically.
2. Description of the Relevant Art
In Japanese Utility Model Patent Application Laid Open No. 43473/1985 (laid open to public inspection on Mar. 27, 1985) a steering system of a vehicle in which a steering handle and steering mechanisms of road wheels are mechanically separated is disclosed. In this steering system, a steering sensor for detecting steering operation is provided on the steering handle. In a front wheel steering mechanism and a rear wheel steering mechanism, motors for driving steering wheels and steered angle sensors for detecting steered angles of the steered wheels are disposed respectively. The front and rear steering mechanism motors are energized in response to output signals from the steering sensors, front and rear wheel steered angle sensors, a speed sensor etc., whereby the front and rear wheels are steered.
In the aforesaid Japanese Utility Model Patent Application Laid Open No. 43473/1985, since the steering handle and the steering mechanisms of the wheels are separated mechanically, the whole steering system can be freely arranged.
In the steering system aforementioned, however, sensors for detecting steered angles of the front and rear wheels are constituted by potentiometers. Thus, at least, for example, a space for partial displacement of an output rod interposed between the motor and wheels is occupied by the potentiometer. As a result, the front and rear steering mechanisms tend to become large. Moreover, since output of the potentiometer is an analog signal, its accuracy is apt to become problematic. In this respect, the problem of accuracy of the detect signal can be solved if a digital linear displacement meter is used in place of the potentiometer. However, while the digital linear displacement meter is relatively costly, the trend of the large-sized steering mechanism still remains.
In view of the problems in the conventional steering system of the vehicle as aforementioned, the present invention has been devised to solve them effectively.